Stereoselective approach to access 3-tert-Butyl-Dimethylsiloxy-2,6-Substituted piperidines through nucleophilic addition of N,O-acetals with organozinc reagents

An efficient approach to access chiral 3-tert-butyl-dimethylsiloxy 2,6-disubstituted 6-benzyl piperidines was developed through nucleophilic addition of N,O-acetals with organozinc reagents. A number of substituted benzyl zinc reagents could react with N,O-acetals 6a-6e, affording the desired products 7a-7j and 9a-9q in good to excellent yields and with high diastereoselectivities.